Within the U.S. Postal Service (USPS) various mail tray configurations are used in conjunction with conveyors to process the mail at a rapid pace. One of these tray types is called the "Small Managed Mail" (SMM) tray, also known as the half tray. These trays are nearly square in shape, actually they are about 14" long and 12" wide when they are made, but, since they are formed of cardboard, they become easily misshapen. They are of such a small size that it is easy for them to become mis-oriented on the conveyor which is transporting them. Frequently these are roller conveyors. When a tray is not correctly rotated it is not possible for automated equipment to properly read bar code labels, or otherwise properly handle these trays. The trays need to be oriented such that the labels are facing forwards or backwards so that they can be read by automated reading equipment.
A mail and package delivery service such as the USPS typically handles millions of items each year. Package handling requires some automation, such as using machine vision, or readers, to read addresses, a necessity in order to deliver all the items to their proper destinations.
In the past there has been no simple, effective way to rotate these trays into the correct orientation, while at the same time insuring that the trays which are already correctly oriented are not rotated into the incorrect orientation.
U.S. Pat. No. 4,512,137 discloses an orienting device for loaves of bread in which the loaves are cut in half and rotated 180 degrees so all loaves on the conveyor are oriented the same. All incoming product is acted on in the same manner.
U.S. Pat. No. 5,421,714 discloses a device for bread dough pieces which, regardless of orientation, centers them on a conveyor and bends them over on themselves prior to baking. No decision is made as to the orientation of the product and all product is acted on in the same manner.
U.S. Pat. No. 4,410,177 deals with bowling pin orientation on a conveyor system. The device is intended to orient on a single axial orientation bowling pins of the type having a relatively heavy base portion and a relatively light neck portion.
U.S. Pat. No. 4,741,429 describes a centering device for irregular ceramic articles on a conveyor line. This device is intended to center the object on the conveyor and is not intended to orient the object to a proper alignment. The device uses two sets of clamps to center the object within the device and then allows the object to be transported along the conveyor. All objects are acted on in the same manner, with the final result being an object "centered" on the conveyor, but not "oriented" on the conveyor.
U.S. Pat. No. 5,299,675 describes a large disc (&gt;5 feet in diameter) which uses centrifugal force to force objects to the outer rim of the disc for purposes of separation and alignment. All objects which enter the device are acted on in the same manner regardless of orientation prior to entering the device. This device will not work with objects which are nearly square in shape, since it depends on the difference in width versus length to accomplish the alignment.